Metering systems exist for measuring current passing through a conductor, such as a utility wire, including an electrical wire, of an industrial power system, without interrupting the electrical circuit being tested. Such metering systems are typically powered by the radiated power from the power system. Such metering systems are typically used with power systems that provide steady power. For example, these metering systems are often used to measure current flowing through utility wires connected to an industrial machine that is in constant operation.
Household power systems, on the other hand tend to have utility wires which are more intermittently powered. One such example is an electrical cord connected to a reading light. When the light is on, power is available in the cord; when the light is off, power is not available in the cord. Such intermittent loading presents challenges not typically found in industrial electrical current metering. For example, metering systems used with such intermittent loads may go long periods without being able to harvest radiated energy from the utility wires.